Cementing plug apparatus



2 Sheets-Sheet l INVENTORS EUGENE E. BAKER GAIL M. BOEHM ATTORNEYS May 30, 1967 E. E. BAKER ETAL CEMENTING PLUG APPARATUS Filed June 11, 1965 BY MIMI, Megivwf N14,-

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May 1967 E. E. BAKER ETAL.

CEMENTING PLUG APPARATUS 2 Sheets-Sheet Filed June 11, 1965 r r, w l

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- '1 m m g I INVENTORS EUGENE E. BAKER GAIL M. BOEHM BY 50 I wwrfufl;

ATTORNEYS United States Patent ()fitice 3,322,197

Patented May 30, 1967 l 2 q 322 197 plunger urges the plunger to retract, thereby camming the dogs outwardly. Movement of the plun er continues, CEMENTIN P APPARATUS since the tubular piston no longer blocks inovement of Eugene E. Baker and Gail M. Boehm, both of Duncan,

th (1 s. Okizu, asslgnors to Halhburton Company, Duncan, 6 egg out of the plunger race S A pressure release port is provided in the sleeve. At Okla. liil d dii e l l, g if l\lo. 463,272 the end of the stroke of the plunger, the release port 11 Clainm ((1 communicates with the high pressure side of the piston. When the end of the stroke of the plunger is reached, the This invention relates to well cementing apparatus, and hydraulic fi uid passes through the release port to the at more particularly to apparatus for selectively releasing mosphere, thereby causing the pressure to drop in the hycementin-g plugs. draulic supply conduit. This drop in pressure is noted by During cementing of wells, a bottom plug is inserted the operator and indicates that the plunger has been fully into the casing ahead of the cement slurry and is pumped retracted. down the casing. A top plug is then inserted in the casing This preferred embodiment is illustrated in the accomon top of the cement. The top plug separates the cement panying drawing in which: from the drilling mud or fluid which is used to force FIG. 1 is a cross sectional view of a cementing plug the cement out through the bottom of the casing and up container having the plug release apparatus of this inventhrough the annular space between the hole and the casing. tion mounted therein; It is important that the plugs be released at the proper FIG. 2 is a cross sectional view of the plug release aptime during the cementing process, so that they can serve paratus with the plunger extended and locked; to separate the cement slurry from the drilling mud or FIG. 3 is a cross sectional view of the apparatus along fluid. Cementing plugs are usually stored in a plug conthe line 3-3 in FIG. 2; and tainer on the top of the casing. A bar or other means sup- FIG. 4 is a cross sectional view of the apparatus showpo-rts the plug in the plug container until the appropriate ing the plunger, retracted. time for releasing the plug. The bar is then removed, A conventional plug containter 2 is. illustrated in FIG. thereby allowing the plug to drop into the casing. Various 1. The lower end of the plug container 2 is adapted to be levers and rods have been proposed for temporarily resecured to the upper end of a casing string. A cementing taining a plug in the plug container. Some of the convenplug 4 is mounted in the plug container and a spring 6 tional plug release devices are capable of being accidentalurges the plug downwardly into the casing string. Move- 1y operated and there is a danger that the plug may be ment of the plug 4, however, is restrained by the plug rereleased prematurely. Also, plug release devices do not lease apparatus of this invention. A lever type indicator have any means for indicating when the latch is released. 10 may be provided on the plug container for indicating Accordingly, it is an object of this invention to provide Whether the plug has passed out of the container. improved apparatus for releasing cementing plugs. The plug release apparatus of this invention includes It is a further object of this invention to provide plug a sleeve 12 which is threaded at one end for mounting the release apparatus which indicates the position of the plug device in a plug container 2. A hexagonal flange 14 is release bar provided on the sleeve 12 for receiving a wrench to It is a still further object of this invention to provide a facilitate threading the sleeve into the wall of the plug plug release device which is eflectively locked in plug container 2. A plunger 16 is mounted on the sleeve 12 for supporting position. reciprocating movement The plunger 16 has a port1on 18 It i another object of this invention to provide a plug of an enlarged diameter and has an annular recess 20. release device for indicating at a remote location when An O t r body 22 is threadedly secured on th d f th the plug retaining bar has been retracted. sleeve 12. The body 22 has an opening 24 in its end wall These objects are accomplished in accordance with the to receive the plunger 16, which is longer than the sleeve preferred embodiment of the invention by a plug release 12 and the body 22. The opposite end of the body 22 has device having a sleeve which extends outwardly from the a counterbore 26 and a tubular retainer piston 28 is side of a plug container. A plunger is mounted in the mounted for reciprocating movement in the fluid chamber sleeve and in its extended position, the plunger prevents between the counterbore Z6 and the Shem/6 A Spring a plug in the plug container from passing into the casing. 30 -g s e piston 28 toward the left, as viewed in In its retracted position, the plunger does not extend into F G- 2- the interior of the plug container, and thus the plug is A pair of dogs 32 are freely mounted in openings 34 free to pass downwardly into the casing. The plunger is in the sleeve 12. The dogs 32 therefore may move radilocked in is extended position by a pair of dogs which ally of the plunger 16 through the openings 34. The thickare mounted in the sleeve and are movable into and out 11685 of the dOgS 32 is greater n t thi kn ss of the of a recess in the plunger. A cylindrical body is mounted a sleeve 12 at the openings 34, and consequently, the dogs on the exterior of the sleeve and a counterbore in one 2 must pr j ct either into the plunger recess 20, or into end of the body forms a cylinder for receiving a retainer the fluid chamber in the body 22. As shown in FIG. 2, piston which is mounted coaxially on the sleeve. The re when the retainer piston 28 is retracted into the fluid tainer piston blocks displacement of the dogs out of the plunger recess when the piston is retracted into the cylthe recess 20. When the piston 28 is in its outward posiinder. The piston is urged into the cylinder by a spring. n, s WII in FIG. 4, however, the dogs 32 are free When the tubular piston is displaced out of the cylinder, t m Ve outwardly through the openings 34 and into the the dogs are free to move outward into the space vacated space between the sleeve 12 and the counterbore 26.

by the tubular piston. Such movement of the dogs is The counterbore 26 in the body 22, the plunger 16 and effected by a cam surface on the plunger which urges the the piston 28 form a chamber for receiving hydraulic dogs outwardly upon retracting movement of the plunger. fluid. The fluid is supplied to the chamber through a con- A piston is formed on the plunger and one side of the pisduit 36. On the upper side of the body 22, there is an ton is in fluid communication with the cylinder. When outlet conduit 38 and a bleed valve 40. While the chamhydraulic fluid is supplied to cylinder, the tubular piston her is being filled with hydraulic fluid through the conis displaced outwardly, thereby allowing the dogs to move duit 36, the bleed valve 40 is open to allow air in the toward the cylinder wall, and the piston portion of the chamber to escape through the outlet pipe 38. When all 3 of the air has been bled out of the chamber, the bleed valve 40 is closed.

Fluid pressure in the chamber acting on the end of the tubular piston 28 imposes an axial force on the piston. When the fluid pressure overcomes the force of the spring 30, the piston moves to the right, as viewed in FIG. 2. The recess is also exposed to the fluid pressure in the chamber, since fluid flows through the openings 34 into the space between the sleeve 12 and the plunger 16. The portion of the plunger to the right of the recess 20, as viewed in FIG. 2, has a smaller diameter than that of the enlarged portion 18. Due to the differential in area of the opposite sides of the recess 20, the fluid pressure in the chamber imposes a resultant force urging the plunger 16 toward the left, as viewed in FIG. 2. O-rings are provided on the plunger 16, piston 28 and sleeve 12 to prevent leakage of fluid out of the chamber.

Movement of the dogs 32 is caused by cam surfaces on the plunger 16 and on the retainer piston 28, as well as corresponding cam surfaces on the dogs themselves. The dogs 32 are urged outwardly against the wall of the counterbore 26 by the sloping side 42 of the recess 20 which engages corresponding cam surfaces on the dogs 32, upon rearward movement of the plunger 16. Of course, the dogs 32 are free to move inwardly against the wall of the cylinder 26, only when the piston 28 has been displaced outwardly to the position shown in FIG. 4. The dogs are urged back into the recess 20 by a cam surface 46 on the end of the piston 28, which engages a corresponding cam surface on the dogs 32. Actual movement outwardly of the dogs 32 can occur, however, only when the recess 20 is aligned with the openings 34. Rearward movement of the piston 28 then displaces the dogs 32 into the recess 20.

When the dogs 32 are in the position shown in FIG. 2, the plunger 16 is locked against rearward movement by engagement of the dogs 32 with the sloping side 42 of the recess 20. However, when the dogs 32 are displaced outwardly to the position shown in FIG. 4, the plunger 16 is free to move toward the left when there is sufficient fluid pressure in the chamber to overcome the frictional resistance. When the plunger reaches the end of the sleeve 12, the enlarged portion 18 engages the body 22 to prevent further retracting movement of the plunger. A pair of pressure release ports 50 and 52 are provided in the sleeve 12 and the body 22, respectively. When the O-ring seal on the enlarged portion 18 of the plunger moves past the port 44, fluid passes into the ports 50, thereby reducing the pressure in the chamber and in the conduit 36.

In operation, when the plunger 16 initially is in the position shown in FIGS. 1 and 2 for supporting a plug in the plug container 2, hydraulic fluid is supplied to the chamber in the body 22 and air is bled off by means of the valve 40. The dogs 32, which are lodged in the recess 20 prevent retracting movement of the plunger 16. When it is desired to release the plug 4, the hydraulic pressure in the chamber is increased until the axial force on the piston 28 overcomes the force of the spring 38 and displaces the piston to the position shown in FIG. 4. At the same time, the fluid pressure acting on the enlarged portion 18 of the plunger 16 causes retracting movement relative to the sleeve 12. The sloping side 42 of the recess 20 cooperates with the cam surfaces 44 on the dogs 32 to urge the dogs outwardly, while the sides of the opening 34 restrict the dogs 32 to movement in a radial direction. When the retainer piston 28 has been displaced outwardly of the counterbore 26, the dogs 32 are free to move outwardly to the position shown in FIG. 4. As soon as the dogs 32 have been displaced out of the recess, the fluid pressure on the enlarged portion 18 of the plunger 16 causes retracting movement of the plunger to the position shown in FIG. 4. When the enlarged portion 18 of the plunger engages the end wall of the body 22, hydraulic fluid behind the portion 18 passes outwardly through the ports 50 and 52, thereby relieving the pressure in the chamber. This drop in pressure also occurs in the conduit 36 and can be monitored on a fluid pressure indicating instrument at a remote location. As shown in FIG. 4, the plunger 16 is fully retracted within the wall of the plug container 2, and the opposite end of the plunger extends out of the body 22 to provide a positive indication that the plunger is fully retracted.

The plug release device of this invention can also be operated manually, provided there is sufficient fluid pressure in the plug container 2 to cause movement of the plunger 16. The piston 28 is provided with a pair of handles, as shown in FIGS. 2 and 3. When it is desired to retract the plunger 16, the handles 54 are pushed toward the right, as viewed in FIG. 2, to overcome the force of the spring 30 and to allow the dogs 32 to move outwardly against the wall of the cylinder 26. Fluid pressure in the plug container 2 acting on the end of the plunger 16 urges the plunger toward the left, as viewed in FIG. 2, and the cam surface 42 on the plunger displace the dogs 32 outwardly suflicientlyto allow the plunger to move to the position shown in FIG. 4. Thus, in the event of a breakdown in the hydraulic supply system, the plug release device may still be operated.

After the plunger 16 has been retracted, it may be returned to its initial position by manually pushing inwardly the end of the plunger 16 that projects through the opening 24 in the body 22 until the recess 20 is aligned with the openings 34. The cam surface 46 on the retainer piston 28 which engages the cam surfaces 48 on the dogs 32 urges the dogs into the recess 20. The piston 28 is urged toward the left, as viewed in FIG. 4, by the spring 30. When the piston 28 has returned to the position shown in FIG. 2, it indicates that the plunger 16 projects into the plug container for supporting a plug in the plug container and that the plunger 16 is locked in this position by the dogs 32. The position of the handles 54, therefore, provides a positive indication of when the plunger 16 is in its extended and locked position.

The plug release device of this invention may be operated from a remote location merely by increasing the fluid pressure in the conduit 36 and then noting the pres sure in the conduit. When the pressure drops, this is an indication that the plunger 16 is fully retracted and the pressure has been relieved by the fluid passing out of the ports 50 and 52. This is particularly important when the cementing operations are carried out at night. It is difficult to see indicators on the plug container that are conventionally used, but a pressure gage may be mounted at a lighted location where it is readily visible to the operator. The position of the handles 54 provides a positive indication of when the plunger 16 is locked in its projected position, while the end of the plunger 16 projecting through the opening 24 in the body 22 indicates when the plunger is fully retracted. The plug releasing device of this invention operates rapidly and reliably for releasing cementing plugs at the appropriate time.

While this invention has been illustrated and described in one embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

We claim:

1. In a plug container, plug release apparatus comprising a plunger, means for mounting said plunger in position for supporting a cementing plug in said plug container, said plunger being longitudinally movable in said mounting means, latch means for locking said plunger in a projected position, and fluid pressure responsive means for releasing said latch means and retracting said plunger, whereby a cementing plug may be released into a well casing when the plunger is retracted.

2. In a plug container, plug release apparatus comprising a plunger, means for mounting said plunger in position for supporting a cementing plug in said plug container, said plunger being longitudinally movable in said mounting means, said mounting means including a cylinder extending coaxially of said plunger, a dog in said cylinder adjacent said plunger, said plunger having a recess therein, means for retaining said dog in said recess and thereby preventing axial movement of said plunger, and fluid pressure responsive means for selectively releasing said retaining means and retracting said plunger, whereby a cementing plug may be released into the well casing when the plunger is retracted.

3. In a plug container, plug release apparatus comprising a plunger, a sleeve, means mounting the plunger for reciprocating movement in said sleeve, means for securing said sleeve to said plug container, a hollow body enclosing a portion of said sleeve, said body and said plunger forming a fluid chamber therebetween, latch means for locking said plunger in a projected position, first piston means in said fluid chamber, said lunger having second piston means thereon, said first and second piston means being in fluid communication with said fluid chamber, said first piston means in one position cooperating with said latch means to prevent unlocking said plunger and in another position releasing said latch means, said sleeve having a release port therein, said port being in position to be uncovered by said second piston when said plunger is retracted, and means for conducting fluid into said fluid chamber, whereby the fluid pressure in the fluid chamber releases the latch means and retracts the plunger, and the ports release the pressure when the plunger is retracted.

4. In a plug container, plug release apparatus comprising a plunger, a sleeve, means mounting the plunger for reciprocating movement in said sleeve, means for securing said sleeve to said plug container, a hollow body enclosing a portion of said sleeve, said body and said plunger forming a fluid chamber therebetween, said plunger having a recess therein, a dog, means mounting the dog for movement radially of said plunger and restricting move ment of said dog longitudinally of said plunger, means for locking said dog in said recess, means forming a piston on said plunger, one side of said piston being in fluid communication with said fluid chamber, means for releasing said locking means in response to fluid pressure in said fluid chamber, whereby said dogs are released from said recess and said plunger is retracted when fluid is supplied to said fluid chamber.

5. In a plug container, plug release apparatus comprising a plunger, a sleeve, means mounting the plunger for reciprocating movement in said sleeve, means for securing said sleeve to said plug container, a hollow body enclosing a portion of said sleeve, said body and said plunger forming a fluid chamber therebetween, said plunger having a recess therein, said sleeve having an opening therein, a dog, said dog being mounted in said opening and in engagement with said plunger, said recess having a sloping side wall forming a cam surface for urging said dog out of said recess upon longitudinal movement of said plunger, means for locking said dog in said recess, means forming a piston on said plunger, and one side of said piston being in fluid communication with said fluid chamber means for releasing said locking means in response to fluid pressure in said fluid chamber, whereby said dog is released from said recess and said plunger is retracted when fluid is supplied to said fluid chamber.

6. In a plug container, plug release apparatus comprising a plunger, a sleeve, means mounting the plunger for reciprocating movement in said sleeve, means for securing said sleeve to said chamber with said plunger movable into position for supporting a cementing plug in said chamber, a hollow body enclosing a portion of said sleeve, said body and said sleeve forming a fluid chamber therebetween, said hollow body having an opening therein, said plunger extending through said opening, said plunger having a recess therein, a dog, means mounting the dog for movement radially of said plunger and restricting movement of said dog longitudinally of said plunger, a retainer piston mounted between said sleeve and said body for reciprocating movement, said retainer piston having a surface communicating with said fluid chamber and having a cam thereon for urging said dog into said recess upon movement of said retainer piston toward said fluid chamber, means biasing said retainer piston toward said fluid chamber, means forming a piston on said plunger, one side of said piston being in fluid communicating with said fluid chamber, and means for conducting fluid under pressure to said fluid chamber, whereby said retainer piston is displaced to release the dogs and the plunger is re tracted.

7. Cementing plug release apparatus comprising a sleeve, a plunger mounted for reciprocating movement in said sleeve, means for securing one end of said sleeve to a plug container, a hollow body enclosing a portion of said sleeve and forming a fluid chamber therein, a retainer piston mounted for reciprocating movement in said fluid chamber, said plunger having a recess therein, a dog, means mounting the dog for movement into and out of said recess, cam means on said plunger for displacing said dog out of said recess upon longitudinal movement of said plunger, said retainer piston in a first positin locking said dog in said recess and in a second position releasing said dog, means forming a piston on said plunger, one side of said piston being in fluid communication with said chamber, and means biasing said retainer piston toward said first position, whereby the dog is locked in the recess until released by supplying fluid to the fluid chamber.

8. Cementing plug release apparatus comprising a sleeve, a plunger mounted for reciprocating movement in said sleeve, means for securing one end of said sleeve to a plug container, a hollow body enclosing a portion of said sleeve and forming a fluid chamber therein, a retainer piston mounted for reciprocating movement in said fluid chamber, said plunger having a recess therein, said sleeve having an opening therethrough, a dog, said dog being mounted in said sleeve opening for movement radially of said plunger, said dog having a greater thickness than said sleeve at said opening, cam means on said plunger for displacing said dog out of said recess, said retainer piston in a first position locking said dog in said recess and in a second position releasing said dog, means forming a piston on said plunger, and means biasing said retainer piston toward said first piston, whereby the dog is retained in the recess until released by supplying fluid to the fluid chamber.

9. Cementing plug release apparatus comprising a sleeve, a plunger mounted for reciprocating movement in said sleeve, means for securing one end of said sleeve to a plug container, a hollow body enclosing a portion of said sleeve and forming a fluid chamber therein, a retainer piston mounted for reciprocating movement in said fluid chamber, said plunger having a recess therein, a dog, means mounting the dog for movement radially of said plunger, said recess having a sloping side forming a cam for displacing said dog out of said recess upon longitudinal movement of said plunger, means forming a piston on said plunger, one side of said plunger piston being in fluid communication with said fluid chamber, said hollow body having an opening in one end, said plunger extending through said opening, cam means between said dog and said retainer piston for urging said dog into said recess, and means for biasing said retainer piston toward said fluid chamber, whereby the plunger is retracted by supplying fluid to the fluid chamber and the plunger projects through said hollow body opening when the plunger is retracted.

10. Cementing sleeve, a plunger said sleeve, means for securing one end of said sleeve to a plug container, a hollow body enclosing a portion of said sleeve and forming a fluid chamber therein, a retainer piston mounted for reciprocating movement in said fluid chamber, said plunger having a recess therein, a dog plug release apparatus comprising a means mounting the dog for movement into and out of said recess, cam means on said lunger for displacing said dog out of said recess upon longitudinal movement of said plunger, said retainer piston in a first position locking said mounted for reciprocating movement in dog in said recess and in a sceond position releasing said dog, said retainer piston having handles thereon, means forming a piston on said plunger, one side of said piston being in fluid communication with said chamber, and means biasing said retainer piston toward said first position, whereby the dog is locked in the recess until released by supplying fluid to the fluid chamber.

11. cementing plug release apparatus comprising a sleeve, a plunger mounted for reciprocating movement in said sleeve, means for securing one end of said sleeve to a plug container, a hollow body enclosing a portion of said sleeve and forming a fluid chamber therein, a retainer piston mounted for reciprocating movement in said fluid chamber, said plunger having a recess therein, a dog, means mounting the dog for movement into and out of said recess, cam means on said plunger for displacing said dog out of said recess upon longitudinal movement of said plunger, said retainer piston in a first position locking said dog in said recess and in a second position releasing said dog, means forming a piston on said plunger, one

side of said piston being in fluid communication with said chamber, said sleeve having a release port therein, said port being in position to communicate with said plunger piston one side when the plunger is retracted, and means biasing said retainer piston toward said first position, whereby the dog is locked in the recess until released by supplying fluid to the fluid chamber.

References Cited UNITED STATES PATENTS 2,058,069 10/1936 Dyer 166-70 X 2,870,842 1/1959 Hall 166-70 2,915,422 12/1959 Stone 16-1()4.06 X 3,218,659 11/1965 Rowley 166--70 X 3,291,217 12/1966 Wakefield 166-70 X CHARLES E. OCQNNELL, Primary Examiner.

JAMES A. LEPPINK, Examiner. 

1. IN A PLUG CONTAINER, PLUG RELEASE APPARATUS COMPRISING A PLUNGER, MEANS FOR MOUNTING SAID PLUNGER IN POSITION FOR SUPPORTING A CEMENTING PLUG IN SAID PLUG CONTAINER, SAID PLUNGER BEING LONGITUDINALLY MOVABLE IN SAID MOUNTING MEANS, LATCH MEANS FOR LOCKING SAID PLUNGER IN A PROJECTED POSITION, AND FLUID PRESSURE RESPONSIVE MEANS FOR RELEASING SAID LATCH MEANS AND RETRACTING SAID PLUNGER, WHEREBY A CEMENTING PLUG MAY BE RELEASED INTO A WELL CASING WHEN THE PLUNGER IS RETRACTED 